I liked the movie, but I think the ending could have been a little less emphatically "final", especially when we already know he's coming back for Avengers 2 and probably more Iron Man movies. It felt a little too obviously fake.

Hmm, I get the critique, but my takeaway wasn't a sense of finality with respect to Tony Stark's identity as Iron Man. What I got from the final post-battle sequences was:

Stark was in a paranoid and unsettled frame of mind when he created all those armors. Now that he was in a more peaceful place, mentally, he thought it would be best to start over. This involved destroying his multiple armors (which might or might not contain embedded abstractions of his manic state of mind), taking out the arc reactor in his chest and going back to basics: "I am Iron Man".